package com.huabo.sql.type;

import com.alibaba.druid.support.logging.Resources;
import com.huabo.sql.record.JSONB;

import java.io.InputStream;
import java.io.Reader;
import java.lang.reflect.Constructor;
import java.lang.reflect.Type;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Created by Jackie Liu on 2017/9/25.
 */
@SuppressWarnings({"ALL", "AlibabaClassMustHaveAuthor"})
public class TypeHandlerRegistry {

    // EnumMap，保存JDBC内部提供的枚举JdbcType类型和对应的TypeHandler
    private final Map<JdbcType, TypeHandler<?>> JDBC_TYPE_HANDLER_MAP = new EnumMap<JdbcType, TypeHandler<?>>(JdbcType.class);
    // Type：javaType的Class类型(Type是Class的接口)，value是一个Map集合（比如String，可能对应数据库的clob、char、varchar等，所以是一对多关系）
    private final Map<Type, Map<JdbcType, TypeHandler<?>>> TYPE_HANDLER_MAP = new ConcurrentHashMap<Type, Map<JdbcType, TypeHandler<?>>>();
    // 处理Object类型（运行时，会尝试进行向下类型转换找到合适的TypeHandler，如果依然失败，最后选择ObjectTypeHandler）
    private final TypeHandler<Object> UNKNOWN_TYPE_HANDLER = new UnknownTypeHandler(this);
    // 所有的TypeHandler. Key：TypeHandler的Class类型，value：TypeHandler实例（都是singleton）
    private final Map<Class<?>, TypeHandler<?>> ALL_TYPE_HANDLERS_MAP = new HashMap<Class<?>, TypeHandler<?>>();

    private static final Map<JdbcType, TypeHandler<?>> NULL_TYPE_HANDLER_MAP = new HashMap<JdbcType, TypeHandler<?>>();

    private Class<? extends TypeHandler> defaultEnumTypeHandler = EnumTypeHandler.class;

    public TypeHandlerRegistry() {
        register(Boolean.class, new BooleanTypeHandler());
        register(boolean.class, new BooleanTypeHandler());
        register(JdbcType.BOOLEAN, new BooleanTypeHandler());
        register(JdbcType.BIT, new BooleanTypeHandler());

        register(Byte.class, new ByteTypeHandler());
        register(byte.class, new ByteTypeHandler());
        register(JdbcType.TINYINT, new ByteTypeHandler());

        register(Short.class, new ShortTypeHandler());
        register(short.class, new ShortTypeHandler());
        register(JdbcType.SMALLINT, new ShortTypeHandler());

        register(Integer.class, new IntegerTypeHandler());
        register(int.class, new IntegerTypeHandler());
        register(JdbcType.INTEGER, new IntegerTypeHandler());

        register(Long.class, new LongTypeHandler());
        register(long.class, new LongTypeHandler());

        register(Float.class, new FloatTypeHandler());
        register(float.class, new FloatTypeHandler());
        register(JdbcType.FLOAT, new FloatTypeHandler());

        register(Double.class, new DoubleTypeHandler());
        register(double.class, new DoubleTypeHandler());
        register(JdbcType.DOUBLE, new DoubleTypeHandler());

        register(Reader.class, new ClobReaderTypeHandler());
        register(String.class, new StringTypeHandler());
        register(String.class, JdbcType.CHAR, new StringTypeHandler());
        register(String.class, JdbcType.CLOB, new ClobTypeHandler());
        register(String.class, JdbcType.VARCHAR, new StringTypeHandler());
        register(String.class, JdbcType.LONGVARCHAR, new ClobTypeHandler());
        //register(String.class, JdbcType.NVARCHAR, new NStringTypeHandler());
        //register(String.class, JdbcType.NCHAR, new NStringTypeHandler());
        //register(String.class, JdbcType.NCLOB, new NClobTypeHandler());
        register(JdbcType.CHAR, new StringTypeHandler());
        register(JdbcType.VARCHAR, new StringTypeHandler());
        register(JdbcType.CLOB, new ClobTypeHandler());
        register(JdbcType.LONGVARCHAR, new ClobTypeHandler());
        //register(JdbcType.NVARCHAR, new NStringTypeHandler());
        //register(JdbcType.NCHAR, new NStringTypeHandler());
        //register(JdbcType.NCLOB, new NClobTypeHandler());

        register(Object.class, JdbcType.ARRAY, new ArrayTypeHandler());
        register(JdbcType.ARRAY, new ArrayTypeHandler());

        register(BigInteger.class, new BigIntegerTypeHandler());
        register(JdbcType.BIGINT, new LongTypeHandler());

        register(BigDecimal.class, new BigDecimalTypeHandler());
        register(JdbcType.REAL, new BigDecimalTypeHandler());
        register(JdbcType.DECIMAL, new BigDecimalTypeHandler());
        register(JdbcType.NUMERIC, new BigDecimalTypeHandler());

        register(InputStream.class, new BlobInputStreamTypeHandler());
        register(Byte[].class, new ByteObjectArrayTypeHandler());
        register(Byte[].class, JdbcType.BLOB, new BlobByteObjectArrayTypeHandler());
        register(Byte[].class, JdbcType.LONGVARBINARY, new BlobByteObjectArrayTypeHandler());
        register(byte[].class, new ByteArrayTypeHandler());
        register(byte[].class, JdbcType.BLOB, new BlobTypeHandler());
        register(byte[].class, JdbcType.LONGVARBINARY, new BlobTypeHandler());
        register(JdbcType.LONGVARBINARY, new BlobTypeHandler());
        register(JdbcType.BLOB, new BlobTypeHandler());

        register(Object.class, UNKNOWN_TYPE_HANDLER);
        register(Object.class, JdbcType.OTHER, UNKNOWN_TYPE_HANDLER);
        //register(JdbcType.OTHER, UNKNOWN_TYPE_HANDLER);

        register(Date.class, new DateTypeHandler());
        register(Date.class, JdbcType.DATE, new DateOnlyTypeHandler());
        //register(Date.class, JdbcType.TIME, new TimeOnlyTypeHandler());
        register(JdbcType.TIMESTAMP, new DateTypeHandler());
        register(JdbcType.DATE, new DateOnlyTypeHandler());
        //register(JdbcType.TIME, new TimeOnlyTypeHandler());

        //register(java.sql.Date.class, new SqlDateTypeHandler());
        //register(java.sql.Time.class, new SqlTimeTypeHandler());
        //register(java.sql.Timestamp.class, new SqlTimestampTypeHandler());

        // mybatis-typehandlers-jsr310
        /*if (Jdk.dateAndTimeApiExists) {
            Java8TypeHandlersRegistrar.registerDateAndTimeHandlers(this);
        }*/

        // issue #273
        register(Character.class, new CharacterTypeHandler());
        register(char.class, new CharacterTypeHandler());

        register(JSONB.class, new JSONBTypeHandler());
    }

    public void setDefaultEnumTypeHandler(Class<? extends TypeHandler> typeHandler) {
        this.defaultEnumTypeHandler = typeHandler;
    }

    public boolean hasTypeHandler(Class<?> javaType) {
        return hasTypeHandler(javaType, null);
    }

    public boolean hasTypeHandler(TypeReference<?> javaTypeReference) {
        return hasTypeHandler(javaTypeReference, null);
    }

    public boolean hasTypeHandler(Class<?> javaType, JdbcType jdbcType) {
        return javaType != null && getTypeHandler((Type) javaType, jdbcType) != null;
    }

    public boolean hasTypeHandler(TypeReference<?> javaTypeReference, JdbcType jdbcType) {
        return javaTypeReference != null && getTypeHandler(javaTypeReference, jdbcType) != null;
    }

    public TypeHandler<?> getMappingTypeHandler(Class<? extends TypeHandler<?>> handlerType) {
        return ALL_TYPE_HANDLERS_MAP.get(handlerType);
    }

    public <T> TypeHandler<T> getTypeHandler(Class<T> type) {
        return getTypeHandler((Type) type, null);
    }

    public <T> TypeHandler<T> getTypeHandler(TypeReference<T> javaTypeReference) {
        return getTypeHandler(javaTypeReference, null);
    }

    public TypeHandler<?> getTypeHandler(JdbcType jdbcType) {
        return JDBC_TYPE_HANDLER_MAP.get(jdbcType);
    }

    public <T> TypeHandler<T> getTypeHandler(Class<T> type, JdbcType jdbcType) {
        return getTypeHandler((Type) type, jdbcType);
    }

    public <T> TypeHandler<T> getTypeHandler(TypeReference<T> javaTypeReference, JdbcType jdbcType) {
        return getTypeHandler(javaTypeReference.getRawType(), jdbcType);
    }

    @SuppressWarnings("unchecked")
    private <T> TypeHandler<T> getTypeHandler(Type type, JdbcType jdbcType) {
        Map<JdbcType, TypeHandler<?>> jdbcHandlerMap = getJdbcHandlerMap(type);
        TypeHandler<?> handler = null;
        if (jdbcHandlerMap != null) {
            handler = jdbcHandlerMap.get(jdbcType);
            if (handler == null) {
                handler = jdbcHandlerMap.get(null);
            }
            if (handler == null) {
                // #591
                handler = pickSoleHandler(jdbcHandlerMap);
            }
        }
        // type drives generics here
        return (TypeHandler<T>) handler;
    }

    @SuppressWarnings({ "rawtypes", "unchecked" })
    private Map<JdbcType, TypeHandler<?>> getJdbcHandlerMap(Type type) {
        Map<JdbcType, TypeHandler<?>> jdbcHandlerMap = TYPE_HANDLER_MAP.get(type);
        if (NULL_TYPE_HANDLER_MAP.equals(jdbcHandlerMap)) {
            return null;
        }
        if (jdbcHandlerMap == null && type instanceof Class) {
            Class<?> clazz = (Class<?>) type;
            if (clazz.isEnum()) {
                jdbcHandlerMap = getJdbcHandlerMapForEnumInterfaces(clazz, clazz);
                if (jdbcHandlerMap == null) {
                    register(clazz, getInstance(clazz, defaultEnumTypeHandler));
                    return TYPE_HANDLER_MAP.get(clazz);
                }
            } else {
                jdbcHandlerMap = getJdbcHandlerMapForSuperclass(clazz);
            }
        }
        TYPE_HANDLER_MAP.put(type, jdbcHandlerMap == null ? NULL_TYPE_HANDLER_MAP : jdbcHandlerMap);
        return jdbcHandlerMap;
    }

    private Map<JdbcType, TypeHandler<?>> getJdbcHandlerMapForEnumInterfaces(Class<?> clazz, Class<?> enumClazz) {
        for (Class<?> iface : clazz.getInterfaces()) {
            Map<JdbcType, TypeHandler<?>> jdbcHandlerMap = TYPE_HANDLER_MAP.get(iface);
            if (jdbcHandlerMap == null) {
                jdbcHandlerMap = getJdbcHandlerMapForEnumInterfaces(iface, enumClazz);
            }
            if (jdbcHandlerMap != null) {
                // Found a type handler regsiterd to a super interface
                HashMap<JdbcType, TypeHandler<?>> newMap = new HashMap<JdbcType, TypeHandler<?>>();
                for (Map.Entry<JdbcType, TypeHandler<?>> entry : jdbcHandlerMap.entrySet()) {
                    // Create a type handler instance with enum type as a constructor arg
                    newMap.put(entry.getKey(), getInstance(enumClazz, entry.getValue().getClass()));
                }
                return newMap;
            }
        }
        return null;
    }

    private Map<JdbcType, TypeHandler<?>> getJdbcHandlerMapForSuperclass(Class<?> clazz) {
        Class<?> superclass =  clazz.getSuperclass();
        if (superclass == null || Object.class.equals(superclass)) {
            return null;
        }
        Map<JdbcType, TypeHandler<?>> jdbcHandlerMap = TYPE_HANDLER_MAP.get(superclass);
        if (jdbcHandlerMap != null) {
            return jdbcHandlerMap;
        } else {
            return getJdbcHandlerMapForSuperclass(superclass);
        }
    }

    private TypeHandler<?> pickSoleHandler(Map<JdbcType, TypeHandler<?>> jdbcHandlerMap) {
        TypeHandler<?> soleHandler = null;
        for (TypeHandler<?> handler : jdbcHandlerMap.values()) {
            if (soleHandler == null) {
                soleHandler = handler;
            } else if (!handler.getClass().equals(soleHandler.getClass())) {
                // More than one type handlers registered.
                return null;
            }
        }
        return soleHandler;
    }

    public TypeHandler<Object> getUnknownTypeHandler() {
        return UNKNOWN_TYPE_HANDLER;
    }

    public void register(JdbcType jdbcType, TypeHandler<?> handler) {
        JDBC_TYPE_HANDLER_MAP.put(jdbcType, handler);
    }

    // java type + handler
    public <T> void register(Class<T> javaType, TypeHandler<? extends T> typeHandler) {
        register((Type) javaType, typeHandler);
    }

    private <T> void register(Type javaType, TypeHandler<? extends T> typeHandler) {
        register(javaType, null, typeHandler);
    }

    public <T> void register(TypeReference<T> javaTypeReference, TypeHandler<? extends T> handler) {
        register(javaTypeReference.getRawType(), handler);
    }

    // java type + jdbc type + handler
    public <T> void register(Class<T> type, JdbcType jdbcType, TypeHandler<? extends T> handler) {
        register((Type) type, jdbcType, handler);
    }

    private void register(Type javaType, JdbcType jdbcType, TypeHandler<?> handler) {
        if (javaType != null) {
            Map<JdbcType, TypeHandler<?>> map = TYPE_HANDLER_MAP.get(javaType);
            if (map == null) {
                map = new HashMap<JdbcType, TypeHandler<?>>();
                TYPE_HANDLER_MAP.put(javaType, map);
            }
            map.put(jdbcType, handler);
        }
        ALL_TYPE_HANDLERS_MAP.put(handler.getClass(), handler);
    }

    // java type + handler type

    public void register(String javaTypeClassName, String typeHandlerClassName) throws ClassNotFoundException {
        register(Resources.classForName(javaTypeClassName), Resources.classForName(typeHandlerClassName));
    }

    public void register(Class<?> javaTypeClass, Class<?> typeHandlerClass) {
        register(javaTypeClass, getInstance(javaTypeClass, typeHandlerClass));
    }

    // java type + jdbc type + handler type

    public void register(Class<?> javaTypeClass, JdbcType jdbcType, Class<?> typeHandlerClass) {
        register(javaTypeClass, jdbcType, getInstance(javaTypeClass, typeHandlerClass));
    }

    // Construct a handler (used also from Builders)

    @SuppressWarnings("unchecked")
    public <T> TypeHandler<T> getInstance(Class<?> javaTypeClass, Class<?> typeHandlerClass) {
        if (javaTypeClass != null) {
            try {
                Constructor<?> c = typeHandlerClass.getConstructor(Class.class);
                return (TypeHandler<T>) c.newInstance(javaTypeClass);
            } catch (NoSuchMethodException ignored) {
                // ignored
            } catch (Exception e) {
                throw new RuntimeException("Failed invoking constructor for handler " + typeHandlerClass, e);
            }
        }
        try {
            Constructor<?> c = typeHandlerClass.getConstructor();
            return (TypeHandler<T>) c.newInstance();
        } catch (Exception e) {
            throw new RuntimeException("Unable to find a usable constructor for " + typeHandlerClass, e);
        }
    }

    /**
     * @since 3.2.2
     */
    public Collection<TypeHandler<?>> getTypeHandlers() {
        return Collections.unmodifiableCollection(ALL_TYPE_HANDLERS_MAP.values());
    }
}
